Internal combustion engine



March 3o, 1943. AY A 'H 2,315,215

INTERNAL COMBUSTION ENGINE Fi1ed 00 1;. 6, 1941 Inventor I A7781. M670 mw Aear Patented Mar. 30, 1943 INTERNAL COMBUSTION ENGINE Karl Maybach, Friedrichshafen,

Germany;

vested in the Alien Property Custodian Application October 6, 1941, Serial No. 413,852 In Germany July19, 1940 6 Claims. i (101. 123-52) My invention relates to internal combustion engines and has special reference to devices for regulating the passages of such engines delivering fuel mixture to the engine cylinders, especially in engines driving cars and having groups of cylinders with separate intake pipes, as for instance engines with a plurality of groups of three cylinders each.

If, for example, in engines of this kind with two groups of three cylinders each the intake manifolds are separated without being interconnected the suction of a cylinder in one group is not affected by the suction of a cylinder of the other group, taking place at the same time, which would happen if the two intake manifolds were interconnected. But it is necessary that the carburetors of each group be so dimensioned as if they had to feed all six cylinders by a common intake manifold. Besides, at the closing of the intake valve of one cylinder of one group because of the high speed of the moving gas column an increase of pressure above atmospheric pressure will result, so that gas mixture escapes into the open air.

A connection between the two separate intake manifolds creates an equalization in pressure and reduces the escape of gas mixture, but still as a throttle effect is necessaiy for avoiding the disadvantageous sucking away of gas mixture by a cylinder of one group from a cylinder of the other group, it is necessary to provide large carburetors to guarantee a sufficient filling of the cylinders. This causes difficulties especially with engines having a large area of numbers of revolution when it becomes necessary to have two or three carburetors for each group, anyhow.

According to my invention I avoid these difliculties by providing an interconnection between both intake manifolds having a control valve operated by the engine in such manner that the twomanifolds are connected with or separated from each other periodically. It is advisable to make the construction so that the separation of the two connecting manifolds is efiected while one or several of the intake valves are closing. Thus, good filling of the respective cylinder is guaranteed, whereas the following re-connection of the two intake manifolds avoids stowage and repressing and loss of fuel mixture and improves the filling of that cylinder which just sucks as now mixture is ifed through bothl manifolds; Consequently, when making use of my invention the carburetors may be dimensioned much smaller because both intake manifolds serve for filling the cylinders.

In certain cases, especially with engines having high speed of rotation, according to my invention additional intake manifolds are provided parallel tothe normal manifolds and one pair or both pairs of manifolds have the engine operated connecting control valve, whereby the Working conditions in such engines are still improved.

The periods during which the control valveor if adequate, a plurality of such valves--are so that a rapid opening to the full cross section of the intake and also a rapid closing is effected; besides, this guarantees wide cross sections in the connecting portion. while it is open. That is why I prefer rotary valves having a cross separating wall for this purpose. The transmission from the engine to such a valve should be so that the valve rotates faster than the engine so as to get a light transmission and a favourable shape of the valve. The construction, according to my invention, as compared with the normal construction, involves a more uniform composition of the fuel mixture burnt in the cylinders, an improvement in the filling, and consequently an increase in output. It is no more necessary with regard to the determination of the control periods of the intake as well as of the exhaust valves to make the usual compromises. The over-lapping of these valves may be avoided more or less. The opening moment of the intake valves may be shifted to the upper dead centre or just behind, the closing moment may be earlier than usual, both causing not only an improvement in filling but also in compression. As now in the upper dead centre the intake valve need not be opened at all or only to a very small extent hardly any exhaust gases may enter the intake manifold, whereas formerly the over-lapping of the valve periods allowed such entering of exhaust gases.

Having given a general description of my invention I now want to point it out more in detail having'reference to the drawing which represents examples embodying my invention.

Fig-1 is a diagrammatic side view on .an internal combustion engine.

Fig. 2 is also a diagrammatic side view but group comprises the three cylinders on the left ij;

with their intakes ll, l2 and. I3, and the second group is indicated by the intakes l4, l5 and 16;

There is a carburetor 3 for the first group and a connecting intake manifold 5, whereas the sec;

nd group has another carburetor 4 with the intake manifold 6. A control member with its 1 housing [8 connects the two manifolds 5 and 6,

as shown in detail in Fig. 3. There is a bevel.

gear drive 8 for rotating the control valve 1 by means of shaft 9 and chain transmission ID. This latter in its transmission ratio is so chosen that valve! rotates once while the crank shaft of the motor makes of one rotation, so that during this time period two cylinders begin or complete their suction period. 7

Control valve 'l-as may be seen from Fig.3 has a middle cross member I! adapted to rotate in the direction of arrow [9 inside of the cylindrical housing l8'which connects the two intake manifolds 5 and 6. The cross section at I8 is larger than that at 5 and 6. V

In Fig. 4 lines 2| and 23 indicate the lifting of the intake valves of cylinders. II and I3, respectively, connected to intake manifold 5, whereas lines 24, 25 and 26 show the lifting of the intake valves of cylinders l4, l5 and I5, respectively, connected to intake manifold 6. The firing order of the engine shown is 1 5 3--6 2 4.

Line 21 indicates the cross section of the con- 7 nection between the two manifolds 5 and 6 controlled by valve 7. All of these lines are drawn diagrammatically over the horizontal axis repres'enting one revolution of the engine crank shaft from 0 to 360 degrees, as indicated.

At 23, for example, at about 140, the cross member ll of valve 1 is assumed to be in the position indicated by'dashed lines in Fig. 3, the connection between the two intake manifolds 5 and6 being now closed until at 29, to which the position of member [1 shown in dash-dotted lines corresponds, the connection re-opens. in the moment in which line 2| meets the horizontal axis, which means-that theintake valve of cylinder I I has just closed. During the following portion of the rotation the connection remains open until it is again closed at 30, to which the position of member I! indicated in dashed lines corresponds. Thus the working of the arrangement is similarly repeatedonly with. intake valves of different cylinders, as may easily be taken from the diagramof Fig. 4.

As between 28 and 29 the connection between the manifolds is lclosed the heavily sucking -cyl-. inder l5 (line 25) cannot badly affect the filling of cylinder H the intake valve of which is just closing (line 2|). And, furthermore, escape of fuel mixture through carburetor 3 after the closing of the intake valve of cylinder. H is avoided as from 29 on the connection between the two intake manifolds is re-opened again rapidly, so that'cylinder l5 will suck not only from manifold 6 but also from manifold 5'thereby preventing over-pressure in the latter. Between 29 and 30 my new arrangement equals one in which the cylinder I5 would be fed by a double carburetor and by an intake manifold of double cross section.

In the modification represented in Fig. 2 the intake manifolds and 36 to which the carburetors 33 and 34, respectively, are connected, correspond to the manifolds 5 and 6, respectively, of Fig. 1. Inaddition thereto there are two intake manifolds 31 and 38 having a connection 39 enclosing control member 40 which is similar to control member I in Fig. 1. Intake manifold 35 These additional intake sections for the admission of fuel mixture and thus improve the filling of the cylinders.

Of course the connection 39 with the control member 40 may as well be inserted between manifolds 35 and 36, or a similar additional connection may be inserted there between.

The groups of cylinders which have a common intake manifold need not be made up of three cylinders each, my invention may be applied to groups of two or four or more cylinders as well. It will also be of advantage with Diesel engines. "I do not want to be limited to the details described or shown in the drawing as many variations will occur to those skilled in the art without deviating from the scope of my invention.

'What I claim is:

1. In an internal combustion having groups of cylinders with an intake manifold for each of said groups, a connection between said manifolds and a control valve in said connection, said control valve being adapted'to open or to close said connection periodically in dependency on the speed of rotation of said engine.

2.'An internal combustion engine as claimed in claim 1 further including means for operating said control valve and a transmission from a rotating element of said engine to said operating means.

3. An internal combustion engine as claimed in claim 1 further including the feature that the cross section of said connection and said control valve when open is larger than the cross sections of said manifolds.

4. An internal combustion engine as claimed in claim 1 further including additional intake manifolds arranged parallel to said first intake I manifolds.

5.'An internal combustion engine as claimed in claim 1 further including an intake valve in said engine,means for operating said intake valve and means for operating said control valve in said connection between said intake manifolds, both said operating means being in such operative connection that said control valve is held closed during a portion of the closing period of said intake valve.

6. In an internal combustion engine having groups of cylinders with an intake manifold for each of said groups, a connection between said manifolds and a control valve in said connection, means for operating said control valve, and a transmission from a rotating element of the 'engine to said operating means operative to 

